In the steel industry, slabs are rolled in the hot state into strips in a hot strip rolling mill. After rolling, the metal sheet runs through a cooling section. The cooling section of the hot strip rolling mill serves to adjust the microstructural properties of the rolled steel strips.
The microstructural properties of the strips produced have previously being derived predominantly from the coiling temperature, which is kept constant at a specified setpoint value by the cooling section automation.
New materials, such as multiphase steels, TRIP steels or the like, require a precisely defined heat treatment, i.e. the specification and monitoring of a temperature profile from the last rolling stand to the coiler.
“Proceedings of ME FEC Kongreβ 99”, Dusseldorf, Jun. 13-15, 1999 (Verlag Stahl Eisen GmbH) discloses a proposal for the automation of hot strip rolling mills in which model-supported control is provided specifically for the cooling section. The cooling is based on the idea that a reference temperature can be specified over the length of the entire cooling section and that the temperature measured at a particular time is adapted to the specified values by means of an adaptive control unit. What is important in this case is that the influence of the cooling can be registered in the longitudinal and vertical directions by means of enthalpies observations and dividing the cooling process into a series of smaller thermodynamic processes. In particular, this involves calculation by means of the method of “Finite Elements”.